1. Field of the Invention
This invention relates to flexural joints for rotating or pivoting members and, more particularly, joints of the type which may be used in pivotal hand tools.
2. Description of the Prior Art
Flexural pivots are used to overcome a number of disadvantages associated with other types of pivot joints. Among the advantages of flexural pivots are the elimination of friction, backlash and wear, lack of requirement for lubrication, insensitivity to contamination and the ability to operate over a wide range of environmental conditions.
One prior type of flexural pivot is disclosed, for example, in U.S. Pat. No. 3,807,029. While that joint affords the above-mentioned advantages, it also has disadvantages. It involves the use of two bushings and two different flexible blade elements. This means that there are four distinct parts which must be fabricated, stocked and assembled to form the joint. Furthermore, the joint, when thus assembled, must in turn be assembled to the pivoting or rotating members of the particular application. Also, in the assembly of the pivot joint, the flexible blade elements must be brazed to the bushings, a costly and time-consuming procedure.
It is known to provide a flexural pivot joint which uses flexible blade elements of substantially identical construction, such an arrangement being disclosed, for example, in U.S. Pat. No. 5,061,107. However, this arrangement also requires the use of two bushings, and the blade ends must be secured by electron beam welding or epoxy adhesive to the bushings.
Another drawback of such prior flexural pivot joints is that they typically have a relatively low compression capacity and, therefore, if substantial axial forces are impressed on the joint, the flexible elements could be permanently deformed, thereby effectively destroying the joint.